presentation for rajita

7/28/2019 Presentation for Rajita

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Introduction Ultracapacitor

Working Principle

Construction

Working Theory

Applications

Advantages and

Disadvantages

Challenges

Conclusion References

Outlines


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In general, capacitor is a device to store the chargein an electric circuit.

Basically, a capacitor is made up of two conductors

separated by an insulator called dielectric.

The dielectric can be made of paper, plastic, mica,

ceramic, glass, a vacuum or nearly any other

nonconductive material.

The electron storing capacity of capacitor is measuredin unit Farads

Introduction


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Ultracapacitors

Ultracapacitors can be defined as a

energy storage device that stores

energy electrostatically by polarising

an electrolytic solution.

Unlike batteries no chemicalreaction takes place when energy

is being stored or discharged and

so ultracapacitors can go through

hundreds of thousands of chargingcycles with no degredation.

Ultracapacitors are also known as

double-layer capacitors or

supercapacitors


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Energy is stored in ultracapacitor by polarizing the electrolyticsolution.

Current Collector

Electrolyte

Separator

Porous electrode

+ _

Principle


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6

Ultracapacitor consists of a

porous electrode(activated

carbon), electrolyte and a

current collector (metal plates).

There is a membrane, which

separates, positive and negative

plated is called separator.

The given diagram shows the

ultracapacitor components.

Construction


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There are two carbon sheet separated by separator.

The geometrical size of carbon sheet is taken in such a way

that they have a very high surface area.

The highly porous carbon can store more energy than any other

electrolytic capacitor.

When the voltage is applied to positive plate, it attracts

negative ions from electrolyte.

When the voltage is applied to negative plate, it attracts

positive ions from electrolyte.

Working


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According to the formula for the capacitance,

Dielectric constant of medium X area of the plate

Capacitance = -----------------------------------------------------------------

Distance between the plates

Therefore, there is a formation of a

layer of ions on the both side of

plate. This is called Doublelayer

formation.

For this reason, the ultracapacitor

can also be called Double layer

capacitor.

The ions are then stored near thesurface of carbon.

The distance between the plates is

in the order of angstroms (1

angstrom = 1.0 10-10 meters).

---

------

---

---

------

---

++

++++

++

+

+

+

+

+

+

+

+

Electrolyte

Separator

Electric double layer

+


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Ultracapacitor stores energy via electrostatic charges on

opposite surfaces of the electric double layer.

They utilize the high surface area of carbon as the energy

storage medium, resulting in an energy density much

higher than conventional capacitors.

The purpose of having separator is to prevent the charges

moving across the electrodes.

The amount of energy stored is very large as compared to a

standard capacitor because of the enormous surfacearea created by the (typically) porous carbon electrodes and

the small charge separation (10 angstroms) created by the

dielectric separator


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Supercapacitors are used in VCRs, CD players, electronictoys,

security systems, computers, scanners, smoke detectors,

microwaves and coffee makers and many more. The

significant applications are-

Heavy transport

Battery complement

Low-power applications

Applications


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Advantage Long life

Rapid charging

Low cost

High power storage

Faster release

Disadvantage Individual cell shows low voltage

They have high self-discharge as compared to battery.

Voltage balancing is required when more than three

capacitors are connected in series.

Advantages and Disadvantages


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The foremost challenge is from traditional batteries such asthe lead acid, lithium ion, nickel cadmium (NiCD), nickel

metal hydride (NiMH) and others which existed in the

market for more than hundred years

Equivalent Series Resistance values can be optimized only

with efficient packaging of the ultracapacitor

Cost of raw materials are significantly high and plays an

important role in the pricing of ultracapacitors

Adoption rates are only gradually increasing as end-users

realize the benefits of ultracapacitors

Challenge


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Ultra capacitors have many advantages over traditional

electrochemical batteries and regular

capacitors.Supercapacitor has longer life,rapid charging

and discharging capability,low cost,high power storage

and many more over the regular capacitors and

batteries.So, it overcomes the loopholes of the regular

capacitors and electrochemical batteries. In future it will

replace the batteries.

Conclusion


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References

http://en.wikipedia.org/wiki/Electric_double-layer_capacitor

http://ultracapacitor.co.kr/

http://whatis.techtarget.com/definition/ultracapacitor

http://ultracapacitor.net/whatareultracapacitors.php

http://www.cleancartalk.com/battery-technology-hybrid-

electric-cars/short-primer-on-ultracapacitors/

http://www.docstoc.com/docs/39619756/Ultra-capacitor


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Thanks everyoneHave a glad day!!!

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